Browse Prior Art Database

Etchable Aluminum-Copper Films On Topography Wafers

IP.com Disclosure Number: IPCOM000101769D
Original Publication Date: 1990-Aug-01
Included in the Prior Art Database: 2005-Mar-16
Document File: 2 page(s) / 68K

Publishing Venue

IBM

Related People

Lloyd, JR: AUTHOR [+6]

Abstract

This article concerns a two-step metal deposition process for producing an aluminum-copper film that is etchable in chlorinated plasma and offers good step-coverage on high topography wafers.

This text was extracted from an ASCII text file.
This is the abbreviated version, containing approximately 58% of the total text.

Etchable Aluminum-Copper Films On Topography Wafers

       This article concerns a two-step metal deposition process
for producing an aluminum-copper film that is etchable in chlorinated
plasma and offers good step-coverage on high topography wafers.

      When copper (up to 4 weight %) is added to aluminum in
conventional Al-Cu sputter deposition processing of high topography
wafers, the etchability of the metal film has been found to depend
upon the extent of copper segregation occurring.  The use of
pre-heated wafers/ substrates in such operations also makes it more
difficult to etch such films. SIM analysis shows a higher copper
concentration near the Al- Cu/oxide interface in the films and more
residue build-up on the etched film.  Step-coverage of films
deposited on non-preheated topography wafers has been found to be
poorer than with the use of pre-heated ones.  In net, it is
preferable to etch Al-Cu films on wafers without pre-heat while
courting the risk of poorer step-coverage on such wafers.  The
disclosed two-step deposition process will overcome this topography
wafer metallization dilemma.

      Referring to the figure:
(1)  An aluminum film 1 is sputtered on a preheated wafer/substrate 2
with surface topography 3 to a thickness sufficient for good step-
coverage;
(2) the sputtered wafer/substrate 2 is then cooled to a temperature
at which extensive copper segregation will not take place and sputter
deposited with the Al-Cu film 4.

     ...